History

Contrary to his companion Beleg, who was on duty in the marches of Doriath, Mablung seems to have been in a position of command in Menegroth. While Beleg usually seems to be away on duty at the borders, Mablung is present at important events.[2]

When leaving Doriath, Mablung is often accompanied by Beleg, this is the case when they go to the Mereth Aderthad as Thingol's messengers,[3] and also in the Nirnaeth Arnoediad in which Beleg and Mablung were the only two Elves from Doriath who took part.[4]

Mablung was in charge to guard Morwen Eledhwen, who had dwelt in Doriath at the time, when she set out to Nargothrond in search of her son Túrin Turambar. Unknown to both Mablung and Morwen, Nienor daughter of Morwen, had joined them.

The women were left back upon Amon Ethir and Mablung set out with a small company to scout Nargothrond as were his orders by Thingol. Yet Glaurung left Nargothrond and Mablung was unable to prevent them both from getting ensnared in the traps of Glaurung the Dragon. He hid from Glaurung and then searched the sacked Nargothrond, finding no sign of Túrin. Glaurung when returning mocked Mablung, sparing his life, and informing him that he had now lost also Morwen and Nienor.

Nienor was found again by Mablung, but he later lost her again when she, her mind wiped by Glaurung, fled from Mablung during an Orc attack. Defeated, Mablung returned to Doriath and due to his failure at Nargothrond he asked Thingol to dismiss him. Thingol though did not agree, for the failure hardly was Mablung's fault, being opposed by an enemy that mighty, he maintained his position. Nevertheless he spent years afterwards searching for Morwen and Nienor.[5]

Mablung went to Brethil when he learned Glaurung was there, and there met Túrin. By admitting Nienor was lost he caused Túrin to realize that Níniel his wife had actually been his sister Nienor, and Túrin killed himself.[6]